There is continued interest in new compounds with affinity for the estrogen receptor. This stems from the discovery of two distinct subtypes of receptors, denoted ERα and ERβ (see Mosselman et al., FEBS Letters 392 (1996) 49-53 as well as EP-A-0 798 378). Compounds which are selective for such subtypes of receptors make it possible to provide a more selective estrogen-receptor related treatment. Advantages can for example be obtained from the different distribution of receptor subtypes in human tissue. This enables treatments with a lower burden of estrogen-related side-effects. Examples of estrogen-related medical treatments which can benefit from selective compounds are those for contraception, for therapy of menopausal complaints, osteoporosis, and estrogen dependent tumour control.